1. Field of the Invention
The present invention relates to a vehicle brake hydraulic pressure control unit which includes a pair of regulator valves which are interposed between a pair of output ports provided on a tandem master cylinder and a pair of hydraulic pressure lines which correspond, respectively, to the pair of output ports, respectively, four normally open electromagnetic valves which are interposed between four road wheel brakes, which correspond to both the output ports with two corresponding to each port, and both the hydraulic pressure lines in such a manner as to correspond to the four road wheel brakes, respectively, a pair of reservoirs which correspond to both the output ports, respectively, four normally closed electromagnetic valves which are interposed between both the reservoirs and the four road wheel brakes, respectively, with each corresponding to one of the reservoirs and each of two of the four road wheel brakes, a pair of pumps which can pump brake fluid from both the reservoirs to pressurize the brake fluid so pumped for outputting to both the hydraulic pressure lines and a pair of suction valves which are interposed between both the output ports and suction sides of both the pumps, respectively, which constituent components are all provided in a common base unit with the normally open electromagnetic valves and the normally closed electromagnetic valves arranged in parallel with each other.
2. Description of the Background Art
A vehicle brake hydraulic pressure control unit has already been known in, for example, Japanese Patent Unexamined Publication No. JP-A-2004-75052 in which a pair of regulator valves, four normally open electromagnetic valves, a pair of reservoirs, four normally closed electromagnetic valves, a pair of pumps and a pair of suction valves are provided in a common base unit.
In the vehicle brake hydraulic pressure control unit of the JP-A-2004-75052, however, the pair of suction valves are provided in the base unit in such a manner as to be arranged out of the four normally open electromagnetic valves and the four normally closed electromagnetic valves which are arranged in parallel with each other, and this leads to an increase in size of the base unit, that is, the vehicle brake hydraulic pressure control unit.